Many electronic devices communicate with each other using wireless local area networks (WLANs), such as those based on a communication protocol that is compatible with an Institute of Electrical and Electronics Engineers (IEEE) 802.11 standard (which is sometimes referred to as ‘Wi-Fi’). In media access control (MAC) layers in IEEE 802.11-compatible interface circuits, traffic from an upper layer typically includes priority tags. These tags are usually considered quality-of-service (QoS) requirements of the current traffic. In response, the MAC layers in the IEEE 802.11-compatible interface circuits may map the priority tags to corresponding access categories (ACs) in order to meet the QoS requirements.
Moreover, traffic in different access categories usually uses or has different content-window sizes and inter-frame spacings (IFSs) to provide QoS differentiation. For example, traffic with a lower-priority access category may have a larger contention-window size, which results in longer backoff time and, thus, this lower-priority access category may have a lower QoS in access to the shared medium or channel. Note that existing IEEE 802.11 standards recognize four hierarchical access categories (ACs), including: AC_VO (voice), AC_VI (video), AC_BE (best effort) and AC_BK (background), which provide the foundation for QoS in Wi-Fi networks.
Recently, in IEEE 802.11 ax standard, it has been proposed that transmissions from different electronic devices or stations, such as station A and station B, may be treated equally regardless of the access categories associated with their transmissions (and, thus, regardless of their QoS requirements). In particular, in the proposed IEEE 802.11ax standard, the backoff time for transmissions from stations A and B may be the same, even though they may have different access categories.
Consequently, this proposal may eliminate the ability to provide access category-based QoS differentiation in IEEE 802.11ax. This loss of QoS differentiation may degrade the communication performance for the higher-priority access-category traffic, and, thus, may frustrate users of the electronic devices and degrade the user experience.